During the first day of testimony in Diane Zamora's capital murder trial, Kristina Mason said that days after the killing her friend had confided that the couple plotted to snap Adrianne Jones' neck and dump her body in a lake.

But Ms. Zamora said she got agitated and attacked Ms. Jones sooner than the couple had planned, Ms. Mason said.

"After they had taken her out to a lake, Diane lost control and began to hit her with a weight over the head," she testified.

She also said that during a late-night conversation at Ms. Mason's house, Ms. Zamora admitted she demanded that boyfriend David Graham shoot Ms. Jones.

Ms. Zamora is accused in the slaying of Miss Jones, allegedly carried out in retaliation for a one-time high-school fling she had with Graham. Ms. Zamora was a freshman at the Naval Academy and Graham was in his first year at the Air Force Academy when they were charged in September 1996.

According to statements Graham and Ms. Zamora have given police, they lured Miss Jones to a secluded road, Ms. Zamora hit the girl with a dumbbell weight, then Graham shot her in the head when she tried to flee.

Prosecutors allege that Ms. Zamora told several friends and her family about the killing.

Later, Ms. Mason testified that Ms. Zamora told her that Graham had killed the girl to "prove his love."

Defense attorney John Linebarger pressed Ms. Mason during cross-examination to explain why she didn't come forward sooner with her testimony and why she at first told a grand jury that she didn't know about Ms. Zamora's alleged role in the killing.

"I was scared that she (Ms. Zamora) would kill me if I told...or someone would come after me," Ms. Mason said.

Linebarger also suggested that Ms. Mason might have concocted details of her story after reading a written confession by Graham that was published in a local newspaper.

After several minutes of questioning, State District Judge Joe Drago seemed irritated with the defense, which at times began to ask for details about Ms. Zamora's friends.

"At this rate we won't finish during my lifetime," Drago said, urging attorneys to speed up their questioning.

Drago also upheld several prosecution objections saying that the questions were irrelevant or would force Ms. Mason to speculate.